Future Earth Climate Scenarios

One of the most important features in Universe Sandbox ² is the ability to simulate Earth’s climate. It’s a relatively simple simulation, but it helps demonstrate exactly how fragile and ever-changing our climate is.

In Alpha 13, you can select possible future scenarios for Earth’s climate. These scenarios simulate the rise in carbon dioxide levels in Earth’s atmosphere caused by human activity up until the year 2100.

To simulate these, we use the same Representative Concentration Pathways used in the latest report from the Intergovernmental Panel on Climate Change (IPCC). These four pathways are projections for the future of greenhouse gas emissions and resulting concentrations in our atmosphere. You can see each pathway’s projections in the graphs below (left: emissions; right: concentration).

CO₂ emissions and associated concentrations generated from the RCP Database.

There are many factors we can consider when looking at what changes will affect emissions. Policies, land use, global population, our attitudes toward production and consumption — these can all have a huge impact on greenhouse gas emissions. Each RCP makes different assumptions about how and when these factors might change.

To stabilize concentrations, decreases in emissions are required, because even when emissions are lowered, CO₂ hangs around in the atmosphere for a long time.

Not only do the scenarios project different outcomes for concentrations, but, importantly, they each follow a unique trajectory based on a range of possible socio-economic changes. One assumes a peak in greenhouse gases in the next decade, while another assumes that there will never be stabilization. (This is simplified for the sake of this introduction; you can learn more here.)

In Universe Sandbox ², you can enable RCPs by selecting the Climate tab in Earth’s properties and toggling “Select an RCP Scenario.” The default is RCP 8 5. Click the (+) icon to select one of the other 4 scenarios.

Once enabled, the pathway’s concentration level will be tied to the simulation year. The change in net radiative energy balance is also specified by the scenarios, and we put that right into our energy balance as a decrease in outgoing infrared energy. This has the effect of increasing the greenhouse effect and ultimately increases the average temperature of the planet. To see how the different scenarios play out, you can graph Earth’s temperature over the course of several decades. Below is a simulation of RCP6 through 2100.

These pathways are not forecasts. But simulating them in Universe Sandbox ² can help you gain a more intuitive understanding of what is possible for the future of Earth’s climate.